Add savepoint benchmark

Cargo.toml

@@ -76,6 +76,10 @@ harness = false
 name = "userspace_cache_benchmark"
 harness = false
 
+[[bench]]
+name = "savepoint_benchmark"
+harness = false
+
 [[bench]]
 name = "lmdb_benchmark"
 harness = false

benches/savepoint_benchmark.rs

@@ -0,0 +1,119 @@
+#![allow(dead_code)]
+
+use std::env::current_dir;
+use tempfile::NamedTempFile;
+
+use rand::Rng;
+use redb::{Database, TableDefinition};
+use std::time::{Duration, Instant};
+
+const TABLE: TableDefinition<&[u8], &[u8]> = TableDefinition::new("x");
+
+const VALUE_SIZE: usize = 3_000;
+const SAVEPOINT_WINDOW: usize = 10;
+
+struct Timing {
+    insert: Duration,
+    savepoint_creation: Duration,
+    savepoint_restore: Duration,
+}
+
+/// Returns pairs of key, value
+fn gen_data(count: usize, key_size: usize, value_size: usize) -> Vec<(Vec<u8>, Vec<u8>)> {
+    let mut pairs = vec![];
+
+    for _ in 0..count {
+        let key: Vec<u8> = (0..key_size).map(|_| rand::thread_rng().gen()).collect();
+        let value: Vec<u8> = (0..value_size).map(|_| rand::thread_rng().gen()).collect();
+        pairs.push((key, value));
+    }
+
+    pairs
+}
+
+fn benchmark(db: &Database, insertions: usize) -> Timing {
+    let mut pairs = gen_data(insertions, 24, VALUE_SIZE);
+    let mut written = 0;
+
+    let mut total_savepoint_creation = Duration::from_micros(0);
+    let mut total_insert = Duration::from_micros(0);
+    let mut first_savepoint = None;
+    for _ in 0..SAVEPOINT_WINDOW {
+        let txn = db.begin_write().unwrap();
+        let mut table = txn.open_table(TABLE).unwrap();
+        let start = Instant::now();
+        {
+            for _ in 0..(insertions / SAVEPOINT_WINDOW) {
+                let len = pairs.len();
+                let (key, value) = &mut pairs[written % len];
+                key[16..].copy_from_slice(&(written as u64).to_le_bytes());
+                table.insert(key.as_slice(), value.as_slice()).unwrap();
+                written += 1;
+            }
+        }
+        let end = Instant::now();
+        total_insert += end - start;
+        drop(table);
+        txn.commit().unwrap();
+
+        let txn = db.begin_write().unwrap();
+        let start = Instant::now();
+        let savepoint_id = txn.persistent_savepoint().unwrap();
+        if first_savepoint.is_none() {
+            first_savepoint = Some(savepoint_id);
+        }
+        let end = Instant::now();
+        total_savepoint_creation += end - start;
+        txn.commit().unwrap();
+    }
+
+    let mut txn = db.begin_write().unwrap();
+    let savepoint = txn
+        .get_persistent_savepoint(first_savepoint.unwrap())
+        .unwrap();
+    let start = Instant::now();
+    txn.restore_savepoint(&savepoint).unwrap();
+    let end = Instant::now();
+    let restore_duration = end - start;
+    txn.abort().unwrap();
+
+    let txn = db.begin_write().unwrap();
+    for id in txn.list_persistent_savepoints().unwrap() {
+        txn.delete_persistent_savepoint(id).unwrap();
+    }
+    txn.commit().unwrap();
+
+    Timing {
+        insert: total_insert / insertions as u32,
+        savepoint_creation: total_savepoint_creation / SAVEPOINT_WINDOW as u32,
+        savepoint_restore: restore_duration,
+    }
+}
+
+fn main() {
+    let tmpfile: NamedTempFile = NamedTempFile::new_in(current_dir().unwrap()).unwrap();
+    let db = Database::builder().create(tmpfile.path()).unwrap();
+
+    let mut table = comfy_table::Table::new();
+    table.set_width(100);
+    table.set_header([
+        "DB size",
+        "insert()",
+        "persistent_savepoint()",
+        "restore_savepoint()",
+    ]);
+    for inserts in [10_000, 20_000, 40_000, 80_000, 160_000, 320_000, 640_000] {
+        let timing = benchmark(&db, inserts);
+        let len = tmpfile.as_file().metadata().unwrap().len();
+        let row = vec![
+            format!("{}MiB", len / 1024 / 1024),
+            format!("{}ns", timing.insert.as_nanos()),
+            format!("{}us", timing.savepoint_creation.as_micros()),
+            format!("{}us", timing.savepoint_restore.as_micros()),
+        ];
+        table.add_row(row);
+    }
+
+    println!();
+    println!("{table}");
+}